PROJECT SUMMARY/ABSTRACT Title: Mechanisms and optimization of endosomal escape for cell delivery applications Controlled manipulation of cells through the precise intracellular delivery of biologically active materials has been a long-term goal for probing of cellular mechanisms and therapeutic interventions. Cellular delivery is however a problem that has not yet been solved. Most techniques remain inefficient, are disruptive to cells and can be toxic. Furthermore, no single approach works for all macromolecular cargo, across cell types, or in every context (e.g. cell cultures vs in vivo). This problem is exacerbated by emerging biological applications continually pushing the boundaries of required delivery efficiencies and versatility (e.g. CRISPR-Cas9 technologies). This project aims to reveal fundamental mechanisms of how to permeate cellular membranes, enabling precise control of the molecules that achieve this cell permeation, and to develop new platforms for cellular delivery. Thus, the proposed studies will significantly advance both understanding and solutions to the cell delivery problem.